Why Two-Thirds of Alzheimer’s Patients Are Women

Neuroscientist Lisa Mosconi wrote The XX Brain to answer one question: why does Alzheimer’s hit women so much harder than men? Her answer runs through hormones, menopause, the weight women carry, and what we can do about it in midlife.

By Teona Abuladze · 6 min read

At 45, a woman’s lifetime risk of Alzheimer’s is 1 in 5. A man’s is 1 in 10.

Women carry the disease from the other side too. About two-thirds of dementia caregivers are women, and more than a third are daughters. Many are doing it while raising children and working, often unpaid, often with little help.

For a long time, medicine explained the gap with one fact: women live longer, and Alzheimer’s is a disease of old age. Mosconi wasn’t satisfied with that.

It starts in midlife

Alzheimer’s doesn’t begin when the symptoms do. Changes in the brain start years, even decades, earlier. So Mosconi asked a different question: what happens to women, and not to men, in their forties and fifties?

Menopause.

Estrogen does more than run the reproductive system. In the brain, it helps neurons turn glucose into energy. When estrogen drops, the brain has to adjust.

In 2021 her team published a study in Scientific Reports. They scanned the brains of women aged 40 to 65 before, during and after menopause, and compared them with men of the same age. Brain structure, connectivity and energy use all shifted across the menopause transition. The changes followed menopause, not simply age.

There was good news in it. After menopause, most of those markers stabilized, and grey matter recovered in key areas. Mosconi called it the brain finding a “new normal.”

But women carrying APOE-4, the strongest genetic risk factor for late-onset Alzheimer’s, showed more amyloid-beta buildup than men with the same gene. For them, midlife may be the window when risk quietly adds up.

“Our study suggests that the brain has the ability to find a new ‘normal’ after menopause, at least in most women.” — Lisa Mosconi

A science that came late

Women were left out of a great deal of medical research for decades. In the United States, they weren’t required to be included in federally funded clinical trials until the NIH Revitalization Act of 1993. Research on animals and cells took even longer: only in 2016 did the NIH start requiring scientists to account for sex in their studies.

That means much of what we know about the aging brain was learned from male bodies. Mosconi’s work is part of filling that gap.

What the book asks of you

The XX Brain is practical. Mosconi writes about food, sleep, stress, movement, and hormones, including how to talk to a doctor about hormone therapy. She looks at chemicals in everyday products that can interfere with hormones. She also writes about the mental load women carry, and how chronic stress shows up in the brain.

It reads like a plan for the second half of life, written by someone with a family reason to care.

A fair note: the lifestyle advice is grounded in good evidence for overall brain health. Whether any single habit prevents Alzheimer’s in women specifically hasn’t yet been proven in large long-term trials. That research is still underway, and Mosconi’s lab is one of the places doing it.

If you want to go further, her 2024 book The Menopause Brain picks up where this one ends.

Sources:

• Alzheimer’s Association, 2026 Facts and Figures — https://www.alz.org/alzheimers-dementia/facts-figures
• AARP, interview with Lisa Mosconi on The XX Brain — https://www.aarp.org/health/brain-health/info-2020/lisa-mosconi-the-xx-brain-interview.html
• Weill Cornell Women’s Brain Initiative — https://neurology.weill.cornell.edu/research/womens-brain-initiative
• Mosconi et al., “Menopause impacts human brain structure, connectivity, energy metabolism, and amyloid-beta deposition,” Scientific Reports, 2021 — https://doaj.org/article/81daf184b2aa468d8c9123d6c47009dc
• NewYork-Presbyterian, “The Brain: A New Normal After Menopause” — https://www.nyp.org/advances/article/neurology-neurosurgery/the-brain-a-new-normal-after-menopause
• NIH Office of Research on Women’s Health — https://orwh.od.nih.gov/about
• WBUR On Point, Mosconi on The Menopause Brain, 2024 — https://www.wbur.org/onpoint/2024/02/28/brain-menopause-women-science-reproductive-biology